21121322500660 has 48 divisors (see below), whose sum is σ = 45922715067600. Its totient is φ = 8150362594304.

The previous prime is 21121322500591. The next prime is 21121322500667. The reversal of 21121322500660 is 6600522312112.

It can be written as a sum of positive squares in 8 ways, for example, as 1148896721956 + 19972425778704 = 1071866^2 + 4469052^2 .

It is a super-2 number, since 2×21121322500660² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121322500667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14570455 + ... + 15954334.

It is an arithmetic number, because the mean of its divisors is an integer number (956723230575).

Almost surely, 2^{21121322500660} is an apocalyptic number.

21121322500660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21121322500660 is an abundant number, since it is smaller than the sum of its proper divisors (24801392566940).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21121322500660 is a wasteful number, since it uses less digits than its factorization.

21121322500660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30526020 (or 30526018 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

Adding to 21121322500660 its reverse (6600522312112), we get a palindrome (27721844812772).

The spelling of 21121322500660 in words is "twenty-one trillion, one hundred twenty-one billion, three hundred twenty-two million, five hundred thousand, six hundred sixty".